* [BUGFIX] memcg CPU hotplug lockdep warning fix
@ 2010-10-08 17:49 Balbir Singh
2010-10-08 18:41 ` Andrew Morton
0 siblings, 1 reply; 4+ messages in thread
From: Balbir Singh @ 2010-10-08 17:49 UTC (permalink / raw)
To: Andrew Morton, KAMEZAWA Hiroyuki; +Cc: linux-mm, linux-kernel
memcg has lockdep warnings (sleep inside rcu lock)
From: Balbir Singh <balbir@linux.vnet.ibm.com>
Recent move to get_online_cpus() ends up calling get_online_cpus() from
mem_cgroup_read_stat(). However mem_cgroup_read_stat() is called under rcu
lock. get_online_cpus() can sleep. The dirty limit patches expose
this BUG more readily due to their usage of mem_cgroup_page_stat()
This patch address this issue as identified by lockdep and moves the
hotplug protection to a higher layer. This might increase the time
required to hotplug, but not by much.
Warning messages
BUG: sleeping function called from invalid context at kernel/cpu.c:62
in_atomic(): 0, irqs_disabled(): 0, pid: 6325, name: pagetest
2 locks held by pagetest/6325:
#0: (&mm->mmap_sem){......}, at: [<ffffffff815e9503>]
do_page_fault+0x27d/0x4a0
#1: (rcu_read_lock){......}, at: [<ffffffff811124a1>]
mem_cgroup_page_stat+0x0/0x23f
Pid: 6325, comm: pagetest Not tainted 2.6.36-rc5-mm1+ #201
Call Trace:
[<ffffffff81041224>] __might_sleep+0x12d/0x131
[<ffffffff8104f4af>] get_online_cpus+0x1c/0x51
[<ffffffff8110eedb>] mem_cgroup_read_stat+0x27/0xa3
[<ffffffff811125d2>] mem_cgroup_page_stat+0x131/0x23f
[<ffffffff811124a1>] ? mem_cgroup_page_stat+0x0/0x23f
[<ffffffff810d57c3>] global_dirty_limits+0x42/0xf8
[<ffffffff810d58b3>] throttle_vm_writeout+0x3a/0xb4
[<ffffffff810dc2f8>] shrink_zone+0x3e6/0x3f8
[<ffffffff81074a35>] ? ktime_get_ts+0xb2/0xbf
[<ffffffff810dd1aa>] do_try_to_free_pages+0x106/0x478
[<ffffffff810dd601>] try_to_free_mem_cgroup_pages+0xe5/0x14c
[<ffffffff8110f947>] mem_cgroup_hierarchical_reclaim+0x314/0x3a2
[<ffffffff81111b31>] __mem_cgroup_try_charge+0x29b/0x593
[<ffffffff8111194a>] ? __mem_cgroup_try_charge+0xb4/0x593
[<ffffffff81071258>] ? local_clock+0x40/0x59
[<ffffffff81009015>] ? sched_clock+0x9/0xd
[<ffffffff810710d5>] ? sched_clock_local+0x1c/0x82
[<ffffffff8111398a>] mem_cgroup_charge_common+0x4b/0x76
[<ffffffff81141469>] ? bio_add_page+0x36/0x38
[<ffffffff81113ba9>] mem_cgroup_cache_charge+0x1f4/0x214
[<ffffffff810cd195>] add_to_page_cache_locked+0x4a/0x148
....
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
---
mm/memcontrol.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 116fecd..f4c5665 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -578,7 +578,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
int cpu;
s64 val = 0;
- get_online_cpus();
for_each_online_cpu(cpu)
val += per_cpu(mem->stat->count[idx], cpu);
#ifdef CONFIG_HOTPLUG_CPU
@@ -586,7 +585,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
val += mem->nocpu_base.count[idx];
spin_unlock(&mem->pcp_counter_lock);
#endif
- put_online_cpus();
return val;
}
@@ -1284,6 +1282,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item)
struct mem_cgroup *iter;
s64 value;
+ get_online_cpus();
rcu_read_lock();
mem = mem_cgroup_from_task(current);
if (mem && !mem_cgroup_is_root(mem)) {
@@ -1305,6 +1304,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item)
} else
value = -EINVAL;
rcu_read_unlock();
+ put_online_cpus();
return value;
}
--
Three Cheers,
Balbir
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [BUGFIX] memcg CPU hotplug lockdep warning fix
2010-10-08 17:49 [BUGFIX] memcg CPU hotplug lockdep warning fix Balbir Singh
@ 2010-10-08 18:41 ` Andrew Morton
2010-10-09 1:15 ` Balbir Singh
0 siblings, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2010-10-08 18:41 UTC (permalink / raw)
To: balbir; +Cc: KAMEZAWA Hiroyuki, linux-mm, linux-kernel
On Fri, 8 Oct 2010 23:19:58 +0530
Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>
> memcg has lockdep warnings (sleep inside rcu lock)
>
> From: Balbir Singh <balbir@linux.vnet.ibm.com>
>
> Recent move to get_online_cpus() ends up calling get_online_cpus() from
> mem_cgroup_read_stat(). However mem_cgroup_read_stat() is called under rcu
> lock. get_online_cpus() can sleep. The dirty limit patches expose
> this BUG more readily due to their usage of mem_cgroup_page_stat()
>
> This patch address this issue as identified by lockdep and moves the
> hotplug protection to a higher layer. This might increase the time
> required to hotplug, but not by much.
>
> Warning messages
>
> BUG: sleeping function called from invalid context at kernel/cpu.c:62
> in_atomic(): 0, irqs_disabled(): 0, pid: 6325, name: pagetest
> 2 locks held by pagetest/6325:
> #0: (&mm->mmap_sem){......}, at: [<ffffffff815e9503>]
> do_page_fault+0x27d/0x4a0
> #1: (rcu_read_lock){......}, at: [<ffffffff811124a1>]
> mem_cgroup_page_stat+0x0/0x23f
> Pid: 6325, comm: pagetest Not tainted 2.6.36-rc5-mm1+ #201
> Call Trace:
> [<ffffffff81041224>] __might_sleep+0x12d/0x131
> [<ffffffff8104f4af>] get_online_cpus+0x1c/0x51
> [<ffffffff8110eedb>] mem_cgroup_read_stat+0x27/0xa3
> [<ffffffff811125d2>] mem_cgroup_page_stat+0x131/0x23f
> [<ffffffff811124a1>] ? mem_cgroup_page_stat+0x0/0x23f
> [<ffffffff810d57c3>] global_dirty_limits+0x42/0xf8
> [<ffffffff810d58b3>] throttle_vm_writeout+0x3a/0xb4
> [<ffffffff810dc2f8>] shrink_zone+0x3e6/0x3f8
> [<ffffffff81074a35>] ? ktime_get_ts+0xb2/0xbf
> [<ffffffff810dd1aa>] do_try_to_free_pages+0x106/0x478
> [<ffffffff810dd601>] try_to_free_mem_cgroup_pages+0xe5/0x14c
> [<ffffffff8110f947>] mem_cgroup_hierarchical_reclaim+0x314/0x3a2
> [<ffffffff81111b31>] __mem_cgroup_try_charge+0x29b/0x593
> [<ffffffff8111194a>] ? __mem_cgroup_try_charge+0xb4/0x593
> [<ffffffff81071258>] ? local_clock+0x40/0x59
> [<ffffffff81009015>] ? sched_clock+0x9/0xd
> [<ffffffff810710d5>] ? sched_clock_local+0x1c/0x82
> [<ffffffff8111398a>] mem_cgroup_charge_common+0x4b/0x76
> [<ffffffff81141469>] ? bio_add_page+0x36/0x38
> [<ffffffff81113ba9>] mem_cgroup_cache_charge+0x1f4/0x214
> [<ffffffff810cd195>] add_to_page_cache_locked+0x4a/0x148
> ....
>
>
> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
> ---
>
> mm/memcontrol.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 116fecd..f4c5665 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -578,7 +578,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
> int cpu;
> s64 val = 0;
>
> - get_online_cpus();
> for_each_online_cpu(cpu)
> val += per_cpu(mem->stat->count[idx], cpu);
> #ifdef CONFIG_HOTPLUG_CPU
> @@ -586,7 +585,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
> val += mem->nocpu_base.count[idx];
> spin_unlock(&mem->pcp_counter_lock);
> #endif
> - put_online_cpus();
> return val;
> }
>
> @@ -1284,6 +1282,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item)
> struct mem_cgroup *iter;
> s64 value;
>
> + get_online_cpus();
> rcu_read_lock();
> mem = mem_cgroup_from_task(current);
> if (mem && !mem_cgroup_is_root(mem)) {
> @@ -1305,6 +1304,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item)
> } else
> value = -EINVAL;
> rcu_read_unlock();
> + put_online_cpus();
>
> return value;
> }
Confused again. There's no mem_cgroup_page_stat() in mainline,
linux-next or in any patches in -mm.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [BUGFIX] memcg CPU hotplug lockdep warning fix
2010-10-08 18:41 ` Andrew Morton
@ 2010-10-09 1:15 ` Balbir Singh
2010-10-09 2:18 ` Greg Thelen
0 siblings, 1 reply; 4+ messages in thread
From: Balbir Singh @ 2010-10-09 1:15 UTC (permalink / raw)
To: Andrew Morton; +Cc: KAMEZAWA Hiroyuki, linux-mm, linux-kernel
* Andrew Morton <akpm@linux-foundation.org> [2010-10-08 11:41:23]:
> On Fri, 8 Oct 2010 23:19:58 +0530
> Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>
> >
> > memcg has lockdep warnings (sleep inside rcu lock)
> >
> > From: Balbir Singh <balbir@linux.vnet.ibm.com>
> >
> > Recent move to get_online_cpus() ends up calling get_online_cpus() from
> > mem_cgroup_read_stat(). However mem_cgroup_read_stat() is called under rcu
> > lock. get_online_cpus() can sleep. The dirty limit patches expose
> > this BUG more readily due to their usage of mem_cgroup_page_stat()
> >
> > This patch address this issue as identified by lockdep and moves the
> > hotplug protection to a higher layer. This might increase the time
> > required to hotplug, but not by much.
> >
> > Warning messages
> >
> > BUG: sleeping function called from invalid context at kernel/cpu.c:62
> > in_atomic(): 0, irqs_disabled(): 0, pid: 6325, name: pagetest
> > 2 locks held by pagetest/6325:
> > #0: (&mm->mmap_sem){......}, at: [<ffffffff815e9503>]
> > do_page_fault+0x27d/0x4a0
> > #1: (rcu_read_lock){......}, at: [<ffffffff811124a1>]
> > mem_cgroup_page_stat+0x0/0x23f
> > Pid: 6325, comm: pagetest Not tainted 2.6.36-rc5-mm1+ #201
> > Call Trace:
> > [<ffffffff81041224>] __might_sleep+0x12d/0x131
> > [<ffffffff8104f4af>] get_online_cpus+0x1c/0x51
> > [<ffffffff8110eedb>] mem_cgroup_read_stat+0x27/0xa3
> > [<ffffffff811125d2>] mem_cgroup_page_stat+0x131/0x23f
> > [<ffffffff811124a1>] ? mem_cgroup_page_stat+0x0/0x23f
> > [<ffffffff810d57c3>] global_dirty_limits+0x42/0xf8
> > [<ffffffff810d58b3>] throttle_vm_writeout+0x3a/0xb4
> > [<ffffffff810dc2f8>] shrink_zone+0x3e6/0x3f8
> > [<ffffffff81074a35>] ? ktime_get_ts+0xb2/0xbf
> > [<ffffffff810dd1aa>] do_try_to_free_pages+0x106/0x478
> > [<ffffffff810dd601>] try_to_free_mem_cgroup_pages+0xe5/0x14c
> > [<ffffffff8110f947>] mem_cgroup_hierarchical_reclaim+0x314/0x3a2
> > [<ffffffff81111b31>] __mem_cgroup_try_charge+0x29b/0x593
> > [<ffffffff8111194a>] ? __mem_cgroup_try_charge+0xb4/0x593
> > [<ffffffff81071258>] ? local_clock+0x40/0x59
> > [<ffffffff81009015>] ? sched_clock+0x9/0xd
> > [<ffffffff810710d5>] ? sched_clock_local+0x1c/0x82
> > [<ffffffff8111398a>] mem_cgroup_charge_common+0x4b/0x76
> > [<ffffffff81141469>] ? bio_add_page+0x36/0x38
> > [<ffffffff81113ba9>] mem_cgroup_cache_charge+0x1f4/0x214
> > [<ffffffff810cd195>] add_to_page_cache_locked+0x4a/0x148
> > ....
> >
> >
> > Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
> > ---
> >
> > mm/memcontrol.c | 4 ++--
> > 1 files changed, 2 insertions(+), 2 deletions(-)
> >
> >
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index 116fecd..f4c5665 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -578,7 +578,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
> > int cpu;
> > s64 val = 0;
> >
> > - get_online_cpus();
> > for_each_online_cpu(cpu)
> > val += per_cpu(mem->stat->count[idx], cpu);
> > #ifdef CONFIG_HOTPLUG_CPU
> > @@ -586,7 +585,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
> > val += mem->nocpu_base.count[idx];
> > spin_unlock(&mem->pcp_counter_lock);
> > #endif
> > - put_online_cpus();
> > return val;
> > }
> >
> > @@ -1284,6 +1282,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item)
> > struct mem_cgroup *iter;
> > s64 value;
> >
> > + get_online_cpus();
> > rcu_read_lock();
> > mem = mem_cgroup_from_task(current);
> > if (mem && !mem_cgroup_is_root(mem)) {
> > @@ -1305,6 +1304,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item)
> > } else
> > value = -EINVAL;
> > rcu_read_unlock();
> > + put_online_cpus();
> >
> > return value;
> > }
>
> Confused again. There's no mem_cgroup_page_stat() in mainline,
> linux-next or in any patches in -mm.
>
Oops, sorry for the confusion. This patch applies on top of the dirty
limit patches posted by Greg. I should have posted this in response to
Greg's posting.
--
Three Cheers,
Balbir
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [BUGFIX] memcg CPU hotplug lockdep warning fix
2010-10-09 1:15 ` Balbir Singh
@ 2010-10-09 2:18 ` Greg Thelen
0 siblings, 0 replies; 4+ messages in thread
From: Greg Thelen @ 2010-10-09 2:18 UTC (permalink / raw)
To: balbir; +Cc: Andrew Morton, KAMEZAWA Hiroyuki, linux-mm, linux-kernel
On Fri, Oct 8, 2010 at 6:15 PM, Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> * Andrew Morton <akpm@linux-foundation.org> [2010-10-08 11:41:23]:
>
>> On Fri, 8 Oct 2010 23:19:58 +0530
>> Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>>
>> >
>> > memcg has lockdep warnings (sleep inside rcu lock)
>> >
>> > From: Balbir Singh <balbir@linux.vnet.ibm.com>
>> >
>> > Recent move to get_online_cpus() ends up calling get_online_cpus() from
>> > mem_cgroup_read_stat(). However mem_cgroup_read_stat() is called under rcu
>> > lock. get_online_cpus() can sleep. The dirty limit patches expose
>> > this BUG more readily due to their usage of mem_cgroup_page_stat()
>> >
>> > This patch address this issue as identified by lockdep and moves the
>> > hotplug protection to a higher layer. This might increase the time
>> > required to hotplug, but not by much.
>> >
>> > Warning messages
>> >
>> > BUG: sleeping function called from invalid context at kernel/cpu.c:62
>> > in_atomic(): 0, irqs_disabled(): 0, pid: 6325, name: pagetest
>> > 2 locks held by pagetest/6325:
>> > #0: (&mm->mmap_sem){......}, at: [<ffffffff815e9503>]
>> > do_page_fault+0x27d/0x4a0
>> > #1: (rcu_read_lock){......}, at: [<ffffffff811124a1>]
>> > mem_cgroup_page_stat+0x0/0x23f
>> > Pid: 6325, comm: pagetest Not tainted 2.6.36-rc5-mm1+ #201
>> > Call Trace:
>> > [<ffffffff81041224>] __might_sleep+0x12d/0x131
>> > [<ffffffff8104f4af>] get_online_cpus+0x1c/0x51
>> > [<ffffffff8110eedb>] mem_cgroup_read_stat+0x27/0xa3
>> > [<ffffffff811125d2>] mem_cgroup_page_stat+0x131/0x23f
>> > [<ffffffff811124a1>] ? mem_cgroup_page_stat+0x0/0x23f
>> > [<ffffffff810d57c3>] global_dirty_limits+0x42/0xf8
>> > [<ffffffff810d58b3>] throttle_vm_writeout+0x3a/0xb4
>> > [<ffffffff810dc2f8>] shrink_zone+0x3e6/0x3f8
>> > [<ffffffff81074a35>] ? ktime_get_ts+0xb2/0xbf
>> > [<ffffffff810dd1aa>] do_try_to_free_pages+0x106/0x478
>> > [<ffffffff810dd601>] try_to_free_mem_cgroup_pages+0xe5/0x14c
>> > [<ffffffff8110f947>] mem_cgroup_hierarchical_reclaim+0x314/0x3a2
>> > [<ffffffff81111b31>] __mem_cgroup_try_charge+0x29b/0x593
>> > [<ffffffff8111194a>] ? __mem_cgroup_try_charge+0xb4/0x593
>> > [<ffffffff81071258>] ? local_clock+0x40/0x59
>> > [<ffffffff81009015>] ? sched_clock+0x9/0xd
>> > [<ffffffff810710d5>] ? sched_clock_local+0x1c/0x82
>> > [<ffffffff8111398a>] mem_cgroup_charge_common+0x4b/0x76
>> > [<ffffffff81141469>] ? bio_add_page+0x36/0x38
>> > [<ffffffff81113ba9>] mem_cgroup_cache_charge+0x1f4/0x214
>> > [<ffffffff810cd195>] add_to_page_cache_locked+0x4a/0x148
>> > ....
>> >
>> >
>> > Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
>> > ---
>> >
>> > mm/memcontrol.c | 4 ++--
>> > 1 files changed, 2 insertions(+), 2 deletions(-)
>> >
>> >
>> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> > index 116fecd..f4c5665 100644
>> > --- a/mm/memcontrol.c
>> > +++ b/mm/memcontrol.c
>> > @@ -578,7 +578,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
>> > int cpu;
>> > s64 val = 0;
>> >
>> > - get_online_cpus();
>> > for_each_online_cpu(cpu)
>> > val += per_cpu(mem->stat->count[idx], cpu);
>> > #ifdef CONFIG_HOTPLUG_CPU
>> > @@ -586,7 +585,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
>> > val += mem->nocpu_base.count[idx];
>> > spin_unlock(&mem->pcp_counter_lock);
>> > #endif
>> > - put_online_cpus();
>> > return val;
>> > }
>> >
>> > @@ -1284,6 +1282,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item)
>> > struct mem_cgroup *iter;
>> > s64 value;
>> >
>> > + get_online_cpus();
>> > rcu_read_lock();
>> > mem = mem_cgroup_from_task(current);
>> > if (mem && !mem_cgroup_is_root(mem)) {
>> > @@ -1305,6 +1304,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item)
>> > } else
>> > value = -EINVAL;
>> > rcu_read_unlock();
>> > + put_online_cpus();
>> >
>> > return value;
>> > }
>>
>> Confused again. There's no mem_cgroup_page_stat() in mainline,
>> linux-next or in any patches in -mm.
>>
>
> Oops, sorry for the confusion. This patch applies on top of the dirty
> limit patches posted by Greg. I should have posted this in response to
> Greg's posting.
I plan to include Balbir's fix (above) in forthcoming memcg dirty
limits series V2. I'm running V2 through tests right now.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2010-10-09 2:18 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-10-08 17:49 [BUGFIX] memcg CPU hotplug lockdep warning fix Balbir Singh
2010-10-08 18:41 ` Andrew Morton
2010-10-09 1:15 ` Balbir Singh
2010-10-09 2:18 ` Greg Thelen
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox